Heat the oven to 425 degrees. Place the red bell peppers on a baking sheet and roast for 20 minutes until the skins blister. Remove them, let cool slightly, then peel off the skins and slice the peppers into strips.
Warm the olive oil in a Dutch oven over medium heat. Add the lamb cubes and cook until browned on all sides, about 6 minutes. Season with a pinch of salt and pepper.
Add the diced onion and minced garlic to the pot. Cook for 3 minutes until the onion softens.
Stir in the harissa paste and cook for 1 minute to release its aroma.
Pour in the diced tomatoes with their juice, the beef broth, and the sliced carrots. Bring the mixture to a simmer.
Lower the heat, cover the pot, and cook for 60 minutes until the lamb is tender.
Add the roasted pepper strips and simmer uncovered for 10 more minutes to blend the flavors.
Taste and add more salt or pepper if needed. Sprinkle with chopped parsley before serving.